Esters of anthracene acid adducts



Patented June 13, 195O ESTERS F ANTHRACENE ACID AldDUCTS Lyle M. Geiger,Edgewood, Pa., assignor to The Neville Company, Pittsburgh, Pa.-, acorporation of Pennsylvania No Drawing. Original application February 2,

1946, Serial No. 645,241. Divided and this application November 2, 1946,Serial No. 707,549 2 This invention relates to esters of adducts formedby the reaction of anthracene and unsaturated organic acids, or acidanhydrides, .and more especially to the plasticizing of organicpolymeric materials, particularly synthetic resins, by such compounds,and this application is a division of my copending application SerialNo.

645,241, filed February 2, 1946.

In addition this invention is concerned with, as new chemical compounds,esters of adducts of anthracene and alpha, beta unsaturated carboxylicacids.

Although certain new and useful compounds are provided by the invention,they are particularly adapted to the plasticizing of commercialplastics, and particularly the vinyl polymers and copolymers, especiallypolymers of vinyl chloride and its copolymers. A wide variety ofplasticizers are, of course, known, and many of them have been usedwidely in the compounding of plastic compositions. A number of qualitiesare desirable in plasticizers such, for exampleas compatibilitylowvolatility, stability, odorlessness, and non-toxicity, and it must berecognized that no single known plasticizercombines allof these desiredproperties although each may have certain advantages for a particularuse. In addition, in many instances there are characteristic propertiesof a specific plasticizer or class of plas= ticizers which bring aboutspecific desirable qualities in the plasticized composition. Thus, aparticular polymeric material may be advantageously plasticized with aparticular class of plasticizer. It is equally true that the knownplasticizers are, as indicated, deficient in various ways forparticular-purposes, being, for example incompatible with otherplasticizers or plastics, or not adapted to particular uses.

The vinyl plasticsexemplify one aspect of this situation and they willtherefore be'referred to by, way of example but not" of limitation. Notonly are they rather diflicult to-plasticize ingeneral, but also up tothe time of this invention it has not been practical to produce by theexisting molding techniques rigid 'vinyl polymer-articles similar innature tothose made from cellulose esters,v such .as the. acetate,nitrate and acetobutyrate, or the cellulose ethers, such as ethyl andbenzyl. This isdueto the-fact that at. the molding temperature used, i.e., about,l'70 to180. 0., the vinyl polymers are thermally unstable.Attempts to overcome this diificulty by the'addition of knownplasticizers, in order to reduce the softening point of the vinylpolymers below the temperature at which.'they'are unstable, have 15Claims. (01. 260-469) failed because the commonly used plasticizers(such'as diakyl phthalates, dialkyl sebacates, di-'- alkyl adipates,triaryl phosphates, Flexol 3-GO= (triethylene' glycol di-z-ethylhexoate)and Flexol 3-GI-I (triethylene glycol di-2-ethylbutyrate and other knowntypesrinherently impart a high degree of elasticity, or rubberiness, tothe vinyl polymer ifthey are present in amounts sufficient to confersafe molding temperatures. Moreover,- the dimensional stability islikewise impaired; In OthGI'IWOI'dS, the addition of large quantities ofthe conventional plasticizers will lower considerably the moldingtemperature of vinyl polymers, but at the same time extremely flexible,rubberlike compositions result. Smaller quantities of. the conventionalplasticizers produce less rub-'" bery compositions, but they do notlower the molding temperature sufiiciently to prevent de-. compositionof the polymer.

Among the less desirable qualities of vinyl resins plasticized with theabove named and other commonly used plasticizers is the exudation orbleeding of pasticizer from the plastic composition, causing loss ofplasticizer with resultant reduced flexibility and elasticity. Thischaracteristic is highly objectionable in articles of'c0m-' merce sincethe plasticizer exuded" may cause considerable damage to surfaces onwhich the articles may be placed, or come in contact, such as lacquered,varnished or painted'protective coatings. This phenomenon, calledsyneresis, r is thought to be caused by a contraction of the gellikestructure of plasticized macromolecular polymers resulting in theforcible ejection of oily plasticizer from the body ofthe plasticcomposition.:., Further, it has been determined experimentally that. thecommonly used plasticizers, including those "listed above, exhibit poorchemical resist-,- ance, particularly inrespect toalkalis. It is wellrecognized by those skilled inthe artthat many synthetic, organicpolymers have outstanding re sistance to chemical reagents, but thatwhen plasticized withrmaterials hitherto available for the purpose,particularly thoseesters listed above, the plastic composition obtainedis considerably inferior in chemical resistance due to the. relativelypoor chemical inertness of the plasticizer component. i V

It is among the objects of the present invention to provide newanthracenederivativesthat-are particularly useful as plasticizers forpolymeric materials, especially synthetic organic polymers, andparticularly the vinyl polymers, and which are compatible therewith sothat the natural appearance and the inherent chemical resistance of thepolymeric material are not altered.

A special object is to provide anthracene derivatives that areespecially suited for use in P ducing rigid vinyl polymer and copolymeproducts, particularly those of or including vinyl chloride, by moldingprocedures.

Still another object is to provide anthracene derivatives suited, amongother uses, for plasticizing vinyl resins without any tendency for theplasticizing constituent to exude or bleed from the plastic composition,and also as plasticizers for use generally in lacquers, spiritvarnishes, varnishes, enamels, paints and other coating compositions.

Other objects will appear from the following description.

I have discovered, and it is upon this that the invention is predicatedin part, that esters of anthracene-carboxylic acid adducts are not onlyof general utility but also provide excellent plasticizers that permitthe attainment of certain objects not heretofore possible orpracticable. The terms adduct and endo as applied to anthracenederivatives herein, are used in the usual sense to designate thoseanthracene derivatives in which a substituent links the median carbonatoms, or is within the ring, or nucleus, of the anthracene molecule, i.e., is linked across the 9, I positions, and they are to be sounderstood in the following specifications and claims.

In the practice of the invention it is preferred for most purposes toform the anthracene adducts from unsaturated dibasic acids such, forexample, as maleic, itaconic, and fumaric acids. The unsaturated acidsare, however, generally utilizable in the practice of the invention,including not only the aliphatic unsaturated monobasic acids such ascrotonic, angelic, acrylic and methacrylic acids, and the dibasic acidsas just indicated, but also aromatic and other cyclic acids having anunsaturated carboxylic side chain, for instance cinnamic acid. Thus theacid adducts formed by reaction of anthracene with. alpha, betaunsaturated monoor dicarboxylic acids, described by Diels and Alder,Annalen 486, 191 (1931), are among the raw materials used in practicingthis invention.

Similarly, the esters of such adducts may be formed by reaction withalcohols generally, i. e., whether primary, secondary, or tertiary, andwhether saturated or unsaturated, examples being the various saturatedalcohols derived from the alkanes, trimethylcarbinol (tertiary),isopropyl alcohol (secondary), and many others, typical examples beingethyl and normal propyl and butyl alcohols, secondary propyl and butylalcohols, isobutyl alcohol, pentanol-2, pentanol-3, methyl isopropylcarbinol, tertiary amyl alcohol, the hexyl, heptyl and octyl alcohols;alcohols having a larger number of carbon atoms, derivatives andsubstituents of the foregoing and related alcohols, and mixtures ofalcohols, either of dilferent numberof carbon atoms or of isomeric formsof those of the same-number of carbon atoms. H

The compounds provided by the invention may be formed also by directreaction-between anthracene and esters of alpha, beta unsaturated acids,if desired. I

The esters of this invention are referred to hereinafter, in the lightof what has been said above, as esters of a monohydric aliphatic alco-1101 containing more than one carbon atom and a Diels-Alder adduct ofanthracene and an alpha,

4 beta ethylenically unsaturated carboxylic acid. I have found that forthe purpose of producing plasticizers embodying the desirable propertiesthat will be pointed out hereinafter it is not necessary to usechemically pure anthracene. For example, good yields of anthraceneadducts having melting points indicating fairly pure products have beenmade by reacting maleic anhydride not only with anthracene of about 99per cent purity, but also with What is known com-- mercially as crudeanthracene, which is a dark greenish-black, crystalline substanceobtained by the cooling of commercial creosote oil, or with theso-called commercial 30-40 per cent anthracene, which is a dark orangecrystalline substance that yields about 32 per cent of anthracene. I

The adduct compounds may be made by heating anthracene and an alpha,beta unsaturated acid together. An inert solvent may be used, such asxylene or other aromatic compound, such as anisole. The resultant adductis then esterified, yielding compounds provided by this invention. Theesterification is performed easily and simplyby heating the adduct andthe alcohol, with an inert solvent if desired, in proportions to formthe desired ester, and most suitably with a small amount, say from about0.1 to 1 per cent, of an acidic catalyst, such as sulfuric, hydrochloricor paratoluene sulfonic acids. The excess of alcohol, if any, togetherwith the water formed by the reaction are distilled off, and the estermay be purified by vacuum distillation. Generally speaking, these estersare of high molecular weight and have extremely low vapor pressures,even at elevated temperatures, so that it. may be difficult to distillthem satisfactorily under ordinary conditions of vacuum operation, butthey can be distilled adequately by the appli cation of moleculardistillation, the principles and application of which are understood inthe art. In the production of the adducts, acid anhydrides may be usedin place of the acids themselves, and in view of the relationshipbetween organic acids and their anhydrides it is to be understood thatthe word acid" as used hereinafter includes both acids and theiranhydrides. The carboxylic group or groups of the unsaturated acids donot participate in the reaction.

An alternative way of preparing the esters, as mentioned before, is toreact anthracene directly with the ester of the desired alpha, betaunsaturated acid. This may be desirable for some purposes because theester is thus produced in a single step, which method is illustrated inthe examples given below for the production of diethyl and dipropylesters of Diels-Alder adduct of anthracene and fumaric or maleic acid.

Diethyl ester.-This exemplifies the direct production of theplasti-cizing ester from anthracene and an unsaturated alpha, betaester. 20 gmQof purified anthracene and 19.3 gm. of diethyl maleate (1:1mol ratio) were heated with 0.1 per cent of iodine at to C. for 5 hours.The product was then taken up in 40 cc. of acetone, and the solution wasfiltered'to remove any unreacted anthracene. Part of the acetone wasthen evaporated under vacuum, whereupon the diethyl ester crystallized,giving a 71.3 per cent yield. The crystalline product was purified byrefluxing it for I hour with 4.8 gm. of activated charcoal in 72 cc. ofpetroleum benzine. After filtration and cooling there was obtained a56.5 percent yield of colorless, crystalline ester melting at 105 to 1060., soluble in"tolu'o1;'actone, xylol, n-butyl 'acetatefisophorone andmethyl ethyl ketone; and soluble 'in' hotn-butanol but less soluble inthe'co'ld.

Dipropyl ester. Thi's isfa further example of r the type of procedureused infmakin'g the diethyl ester. gm. of purified anthracene and 22.5gm. of n-propyl malea'te (1 :1rnol ratio) were reacted and treatedsnbstantiallyas'in' the foregoing example. The yield of the crude esterwas 75.3 per cent; The purifiedester was recovered as white, crystallinematerial melting at 100 to 101 C., and in a yield of 51.8 per cent,'andthe product had the same solubility"characteristics as the diethylester. 11 I In the process of preparing the esters embodied in thisinvention I may use the adduct of-,anthracene and maleic acid (or itsanhydride)"a'ndles terify it with an alcohol. 'A wide-variety'of esters,all of which I believeto'be new, have been 20 prepared by this method,examples of which fol low, using Diels-Alder-adduct of anthracene andmaleic anhydride and various primary alcohols. Dz'butyl ester.308 gm. ofcrude anthracene maleic anhydride adduct and 223 gm. of n-butanol wereheated with 13.7 gm. of p-toluene sulfonic acid for 6 hours at 115 to185 C. Water was removed continuously by applying vacuum and bleedingair through the solution The crude ester was taken up in 400 gm. ofpetroleum benzine, 28 gm. of activated charcoal were added, and themixture was refluxed for hour. There were then added 20 gm. ofpowderedcaustic soda while agitating the mixture. After filtration the solutionwas cooled and by filtration the dibutyl ester was recovered as whitecrystals melting; at

about 54 to C. The yield was 42.5 per cent, H r

and the product was soluble incarbon tetra chloride, chloroform,aromatic hydrocarbons, acetone, n-butanol, methanol, isophorone, n-butylM) acetate, methyl ethyl ketone, and cyclohexane. Other properties areas follows:

Melting point, 0.-. 54 cm Color Colorless l 5 Form Crystals,

Specific gravity at 25 C.-. 1.1153 Ester value, per cent theory 97Solubility: a 50 Petroleum benzine Sol. hot, insol. cold Heptane Sol.hot, insol. cold Isopropanol Sol. hot, less sol. cold Di Z-ethyZhexyZ)ester.l03.6 parts ojanthracene maleic anhydride adduct melting at 258?C. and 146.4 parts of 2-ethylhexanol (1:3 inclratio)- were mixed with5.2 partsof p-toluenes'ulfonic acid and heated during 2 hours at C. Theexcess alcohol was distilled ofiat reduced pressure. The crude productwas taken up in an equal volume of petroleum benzine, and it was thenrefluxed with powdered sodiumhydroxide to neutralize it, after which itwas refluxed with 10 per cent by weight of active charcoal, based G5upon the theoretical ester yield. The solvent was then recovered byvacuum distillation with 0. maximum liquid temperature. The total yieldwas 98.5 per cent of theoretical, and the product was soluble in carbontetrachloride, 7o chloroform, aromatic hydrocarbons, acetone, iso-'propanol, n-butanoL-isophorone, n-butyl acetate, methyl ethyl ketone,heptane, petroleum benzine and cyclohexane. Other properties are as folMaratitaa,1 e.;;; ea t lea. 'f. Color Pale Amberto colorless FormResinous liquid EstersojDiels-Alder adduct 0) anthracene and crotom'cacids-The anthracene-scrotonic acid adcluctthought to have thisstructure:

was prepared according to the method described by Diels and Alder,Arlnalen 486, 191-202, 1931. Esters of'this adduct are easily preparedby the conventional methods of esterification already described above.

Esters of 'anthracene'ltaconic acid adduct- 11 parts of anthracene, 8parts of itaconic acid, 50 parts of anisole, 0.04 part of iodine, and0.04 part of hydroquinone were mixed and heated to reflux at -1601C.,with stirring, for 7 hours. On cooling and evaporation of the anisole,15 parts of a tan-colored crystalline material were obtained which uponrecrystallization from chlorobenzene yielded a white crystalline solidmelt ing at to 192 C., thought to be of the following structure:

H o-oooH l H H Esters of this adduct are easily prepared by theconventional methods of esterification as described above. w

Esters of anthracene-Fumaric acid adduct. Anthracene 9.9 parts andfumaric acid 6.4 parts together with 150 parts of anisole were heated toreflux at 150-155 C. for 9 hours with stirring. On cooling-there wasobtained 15 parts of product which was recrystallized from a mixture of80 parts of chlorobenzene and 20 parts of methyl ethyl ketcne, therebyyielding 11 parts of fine,

white crystals whose melting point was 241 to 243 C.; theproduct wasidentified as trans form of Diels-Alder adduct of anthracene. and 1,2-ethylene dicarboxylic acid.

cording to i the method given under previous examples involvingesterification, and there was form of the dibutyl ester of Diels-Alderadduct of anthracene and 1,2-ethylene dicarboxylic acid.

These esters are, to repeat, characterized by properties that renderthem particularly useful as plasticizers and compounding ingredients fora wide variety of polymers. Particularly, they are adapted to theplasticization of vinyl resins. This class of resins includes polymersand copolymers of such compounds as vinyl acetate, vinyl propionate,vinyl butyrate, w'nyl chloride, vinyl benzene (styrene), and likematerials. It also includes the products of reaction between polyvinylacetate and aldehydes, known as polyvinyl formal, polyvinyl acetal,polyvinyl butyral, etc. These esters are likewise well adapted forplasticizing vinylidene chloride polymers. This general plasticizingability may be exemplified by the data of the following tables whichillustrate the compatibility of the foregoing esters, exemplified by theesters identified at the top of each table, with a large number ofchemically unrelated plastics, determined by films cast on glass. Thecolumn headed per cent resin solution gives the concentration of theparticular resinous material listed in the first two columns and thesolvent used to dissolve it, the concentration being in weightpercentage. The esters were dissolved in the solution to yield a finalsolids ratio of 1 part of the ester to 2 parts of the resin. Thus,highly useful lacquers are formed capable of many modifications, as iswell known in the art.

TABLE I Di-ethyl ester of Diets-Alder adduct of anthracene and 1,2ethylene dicarboxylic acid I Commit Nature Material Chemical Nature PerCent Resin Solution oi Soln ible Film Methyl Methacrylate.l -in TohmlYes Clear Clear Ethyl Cellulose. Cellulose Ethyl Ether 6-80 Teluol; 20Acetone Yes do- Do. rmite Urea-formaldehyde condensate GO-n-Butanol D0,Vmylite AYAF Vinyl Acetate Polymer 10-80 Xylol; 20 Isophorone. Do.Nitrocottom... Cellulose Nitrate l0n-Butyl Acetate Do. Formvar. .lPolyvinylformal 10-60 Toluol; 40 Isopropyl Alcohol Do. Melamine 580-9 1Mellamine-Formaldehyde con- 50-11-Bntanol Yes do.. Do.

ensa e. Polystyrene Styrene Polymer l0-Toluol l Yes-- do Do. Hercose CCellulose Aceto-Butyrate Ester" IO-Methyl Ethyl Ketone Yes do Do.

1 Ester did not dissolve in the Ul'ormite and Melamine solutions until alittle toluol was added. All films dried hard and clear except theMelamine and Uformite, which remained solt and clear with a slight tack.

TABLE II Di-propyl ester of Diels-Alder adduct of anthracene and 1,2ethylene dicarboxylic acid C0mpat Nature Material Chemical Nature PerCent Resin Solution I o! Soln Film ucite Methyl Methacrylate Polymer---Cellulose Ethyl Ether D Urea-formaldehyde- Vinyl Acetate Polym 10-80Xylol; 20 Isophor l0-n-Butyl Acetate Do. 10-60 Toluol; 40 Isopropy Do.Melamine-formalde yd 50-n-Bntan nl Do.

sa e. Polystyrene. Styrene Polymer l0-Toluol Do, Hercosc C CelluloseAceto-Butyiate Ester-- IO-Methyl Ethyl Ketone D0,

1 Ester did not dissolve in the Uformite and Melamine solutions until alittle toluol was added. All films dried hard and clear except theMelamine and Uformite, which remained soft and clear with a slight tack.

TABLE III Di-butyl were; Diels-Alder adduct of anthrwcane and 1,2ethylene dicarbomylic acid Compat- Nature 1 Material Chemical NaturePercent Resin Solution ible of Film Sol n.

Methyl Metacrylate Polymen.-- 20-in T l nl Ethyl Cellulose- CelluloseEthyl Ether 6-80 T011101; 20 Acetone Uformite Urea-formaldehydec0ndensate- -l1-Biif:a.nnl l Vinylite AYAF. Vinyl Acetate Polymer 10-80Xylol; 20 Isophorone Nitrocotton Cellulose Nitrate lO-n-Butyl AcetateFormvar.-- Polyvinyliormal 10-60 Toluol; Isopropyl Alcoholnn Geon 101Vinylchloride polymer 591.5 Methyl Ethyl Ketone; 8.5

Oyclohexanone. Goon 202 Vinylchloride vinylidine chlo- 8-90 Methyl EthylKetone; 10 Cycloride copolymer. hexanone. Melamine a.Melamine-formaldehyde conden- BO-n-Bn nnl sa e. Polystryene StyrenePolymer lo-Toluol Hercose O Cellulose Aceto-Butyrate Ester IO-MethylEthyl Ketone Cellulose Acetate Cellulose Acetate 5- o Vinylite VYHH...Viayl lChloride-Vinyl Acetate 10-50 Methyl Ethyl Ketone: Xylene- Yes doDo.

opo ymer.

v All films dried hard and clear except the Melamine and Ulormite. whichremained soft and clear with a slight tack.

' TABLE IV Di (2- eth1lZhe;cz/Z) ester of Diels-Alder adduct ofAnthracene and 1,2 ethylene dicarboxylic acid 1' Compat- Nature MaterialChem cal Nature I Percent Resin Solution ible of Film Sol 11 MethylMethacrylate Polymer 20-ln 'Inlunl Ypq G1 Clean Cellulose Ethyl Ether6-80 T111001; 20 ne Yes do Do,

. Urea-formaldehyde condensate 60-n-Butanol Ypq do Do, Viu lite AYAFVinyl Acetate Polymer l80 Xylol; 20 Isophorone Yes do Do. NitrocottonCellulose Nitrate -n-Butyl Acetate Yes do Do. Formvar Polyvinylformal1060 Toluol; 40 Isopropyl Alcoho1 Yes do Do, Melamine 586-9Melamine-formaldehydeconden- 5011Butanol Ypq do Do,

' sa e.

l Polystyrene Styrene Polymer l0-Toluol Yes do Do, Hercose C CelluloseAeeto-Butyrate Ester 10-Methyl Ethyl Ketone Yes do Do,

All films dried hard and clear except the Melamine and the Uformite,which remained soft and clear with a slight tack.

As further showing the utility of these esters, As pointed out above, ithas not been pracin n h r series of experiments 3 parts. by ticable toproduce rigid vinyl polymer articles weight of vinyl resins were mixedwith 2 parts of the dibutyl ester of Diels-Alder adduct of by known,molding techniques. I have found,

anthracene and 1,2 ethylene dicarboxylic acid, and thls 1S anlmportamfeature of the Invenl and the mixture was milled on a steam heated tion'h t esters describedt for example the rubber mill at 150"" C. Thematerials used and foregomg dlbutyl and dliz'ethyl'hexyl) esters of thecharacteristics of the products are given in Diels-Alder addllct 0fanthracene 811101.12 e y Table V: I E ene dicarboxylic acid, can beappliedv to that TABLE V Material chemical Nature v 0 $5332; $3 3Vinylite VYNW Vinyl chloride-vinyl acetate copolymer- Light... Clean";Yes. Vinylite VYNS Vinyl Chloride-vinyl acetate copolymcr do do Yes.Geon 101 Vinyl Chloride Polymer do do Yes. Geon 202 Vinyl ChlorideCopolymer d do Yes.

Also the di (2-ethyl hexyl) ester of Dielsend. Thus, the addition ofsuch esters to the Alder adduct of anthracene and 1,2 ethylene vinylpolymers and copolymers lowers the molddicarbo-xylic acid was milled inthe same way as 40 ing temperatures sufficiently to permit the proin theforegoing example, using the same reladuction of plastic articleswithout decomposition tive proportions. Results are given in Table VI.or producing dimensional instability, and the TABLE VI Material,Chemical Nature Color a 332;

Vinylite VYNW Vinyl Chloride-vinyl Acetate Copolymer Light..- Clean---Yes. Vinylite VYNS- Vinyl Chloride-vinyl Acetate Copolymer do do Yes.Geon 101--- Vinyl Chloride Polymer do do Yes. Geon 202 Vinyl ChlorideOopolymer do do Yes.

The plasticized compositions listed in Tables products are non-rubberyand are crystal clear,

V and VI were then subjected to heat and pres- "light colored and tough,and rigid at room temsure in a hydraulic press with heated platens.perature. k p es varied from 120 C. to 165 C. in As further exemplifying'the'desirable nature various experiments and pressures were varied 1 ofth t r in comparison t previous1y from 5 p d p Square inch to 12,900pounds known plasticizersfor vinyl polymers, a test was Square There s?"clear, carried. outcomparing the action of the dibutyl highlytransparent smooth sheets of rigid pl ester of Diels-A lder adduct ofanthracene and The Sheets Pbtamed 115mg the (ha-ethyl 11,2 ethylenedicarboxylic acid with di(2-ethyl hexyl) ester of Diels-Alder adduct ofanthracene l'hexyl) phthalate sometimes called dioct 1 l y and 1,2ethylene dicarboxyllc acid were the more (istphthalaten which is v oneof the commo n1 used flexible. Each possessedahard surface and were" 5.FT y out of range of a test instrument known to commercla f 1131s mafiaof Vanous those skilled in the art as a Durometer, type A. blend? ofVmyhte VYHH Vmyl Sheets of plasticwere prepared from the ,same Lcopolymer each of the two plasm vinyl resins and ,Flexol 3 GO, a typicalb o cizers were cast and their hardnesses were deterticizer, and alsofrom the same vinyl resins and mined by wilkinsons Pencil method asdescribed di(2 ethy1 hexyl) phthalate, the same propor in Gardner'sPhysical and Chemical Examinations and conditions being observed In a fltions of Paints, varnishes, Lacquers and Colors case, elastic, rubbery,soft and even sticky, but .i; (Washington, 1939) all p The fi ms we enon-rigid plastic sheets were'obtaine'df""" heated at C., and thehardness was deteri i mined at various time intervals. given in TableVII:

TABLE v11 From the foregoing table it appears clearly that although thesoftening action of the dibutyl ester of this invention on VinyliteVYI-lI-I is slightly less than that of the phthalate platicizer,

- the former is considerably more stable to heat and is retained muchbetter in the exposed film. As

a matter of fact, the estersprovided by this invention are characterizedby extremely low volatility and therefor plastic compositions containingthem are rendered much more permanent than is the case with ordinarycommercial plasticizers.

A further advantage of these anthracene adduct esters is that they arecompatible with all ester types of plasticizers and may therefore beused in mixture with them. Such mixtures maybe applied, for example,'t0confer greater elasticity and rubberiness than is obtained with theadduct ester alone while at the same time providing plasticizedcompositions that are more stable to heat and more permanent thansimilar compositions not containing the adduct ester.

vVarious results may be had in this way. Thus by using the esters ofthis invention in combination with phthalate plasticizers one obtainsthe advantages of both, and the former may act, 4

according to physico-chemical principles, to reduce the volatility ofthe latter, thus improving the stability of the products,

The esters of this invention are generally characterized by beingodorless, tasteless, colorless and stable to heat and light. They do notrender plastic compositions tacky, and synthetic organic resinscompounded with them show excellent adhesion and cohesion. Thesecombinations of properties render the adduct esters of this in- Theresults are l have found, however, that in the case of esters v of theanthracene-maleic acid adducts there is full compatibility with plasticsin general in the case of esters formed from alcohols containing morethan 1 up to at least 8 carbon atoms. In general, the higher the meltingpoint. of the ester the greater the rigidity of vinyl compoundsplasticized with it.

When the esters are those of alcohols having 12 or more carbon atomsthey may no longer be completely compatible with some of the com-, monlyused synthetic organic polymers, but this and other similar esterscontainin longer alkyl chains may be used for the plasticizing of butylrubber (copolymer of isobutylene and butadiene) polythenes (ethylenepolymers), and the like polymeric materials in the form of longmacromolecules. The octadecyl ester may be prepared as described by thefollowing example.

n-Octadecyl ester.-'55.2 gm. of crude Diels- Alder adduct of anthraceneand 1,2 ethylene dicarboxylic anhydride and 108.2 gm. of n-octadecylalcohol were heated with 2.8 gm. of p-toluene sulfonic acid at to C.for6 hours. Water was removed as described in connection with the dibutylester. The product was taken up in 20 cc. of n-hexane, and the solutionwas cooled and filtered. Excess acid was neutralized by adding 22.5other 20 per cent sodium hydroxide solution, followed by repeated waterwashings. The solutionwas then refluxed 1 hour with 30 gm. of activatedcharcoal and 15 gm. of fullers earth, after which it was filtered andthe hexane then distilled off. The ester was a wax-dike opaque palebrown solid having a hard glossy surface, and it melted at 40 C. and wassoluble in toluol, xylol, hexane and n-butyl acetate, and was insolublein alcohols and ketones. I Ifhis ester is completely compatible withethyl cellulose, polyethylene, butyl rubber, GR-S rubber, naturalrubber, and nitro-cellulose. It is partly compatible with Lucite,Uformite, Vinylite VYNW and incompatible with Vinylite AYAF-and Formvar.

Because of the relationship between maleic and fumaric acids, as well asothers utilizable for the purposes of the invention, it will beunderstood that the esters formed from their anthracene adducts willexhibit cis-trans isomerism. Thus, each acid will produce Diels-Alderadduct of anthracene and 1,2 ethylene dicarboxylic acid, but it would beexpected that the maleio and fumaric adducts would be, respectively, cisand trans forms of that acid as shown below for the dibutyl esters;

obi

wont

Likewise, the adduct made from maleic anhydride can exist in only oneform but the possibility exists that a mixture of geometric isomers mayresult from the esterification reaction. In this connection, thefollowing data on highly purified materials are of interest:

Ester ADiels-Alder adduct of anthracene and maleic anhydride esterifiedwith butyl alcohol. Ester M. P. 57.5-59 C.

Ester Bfrom anthracene and dibutylmaleate.

Ester M. P. 50-51.5 C.

Ester C--anthracene-fumaric acid adduct esteritied with butyl alcohol.Ester M. P. 5052 C. Ester C would be expected to be the transform.

A mixed melting point with ester 13 showed no change, indicating thatthe latter is the trans form also. However, mixed melting points ofester A with either ester B or ester C were about 47 0., indicating thatester A is the cis form, as would be expected. Whether or not there isactually cis-transisomerism where the possibility exists in the estersprovided by this invention, the fact is that in the many esters preparedand tested any difierence due to isomerism, or to the proportions ofisomers present, has not detectably altered the physical properties toan extent where the plasticizing power of the esters, for instance asapplied to synthetic organic polymeric substances has been impaired.

According to the provisions of the patent statutes, I have explained theprinciple and mode of practicing my invention and have described what Inow consider to represent its best embodiment. However, I desire to haveit und rstood that, within the scope of the appended claims, theinvention may be practiced otherwise than as specifically described.

I claim:

1. As a new chemical compound, a non-resinous ester having the formulain which R is a member of the group consisting of an alkyl groupcontaining at least two carbon atoms, a substituted alkyl groupcontaining at least two carbon atoms, an aryl group, an alkaryl group,and an aralkyl group.

2. As a new chemical compound, a non-resinous ester of Diels-Alderadduct of anthracene and an ethylinical-ly unsaturated carboxylic acidand an aliphatic monohydric alcohol containing at least two carbonatoms.

3. As a new chemical compound a non-resinous diester of Diels-Alderadduct of anthracene and an ethylenically unsaturated dicarboxylic acidand a monohydric aliphatic alcohol having more than one carbon atom.

4. As a n w chemical compound, a non-resinous diester of Diels-Alderadduct of anthracene and maleic acid and an aliphatic monohydric alcoholhaving more than one carbon atom.

5. As a new chemical compound, a non-resinous diester of Diels-Alderadduct of anthracene and fumaric acid and an aliphatic monohydricalcohol having more than one carbon atom.

6. As a new chemical compound, non-resinous diethyl Diels-Alder adductof anthracene and an acid of the group consisting of maleic and fu-maric(acids.

7. As a new chemical compound non-resinous dibutyl Diels-Alder adduct ofanthracene and an acid of the group consisting of maleic and fumaricacids.

8. As a new chemical compound non-resinous di(2-ethyl hexyl) Diels-Alderadduct of anthracene and an acid of the group consisting of maleic andfumaric acids.

9. As a new chemical compound non-resinous dioctadecyl Dials-Alderadduct of anthracene and an :acid of the group consisting of maleic andfumaric acids.

10. As a new chemical compound non-resinous dibenzyl Dials-Alder adductof anthracene and an acid of the group consisting of maleic and. fumaricacids.

11. As a new chemical compound, a non-resinous ester of Diels-Alderadduct of anthracene and crotonic acid and an aliphatic monohydricalcohol containing more than one carbon atom.

12. As a new chemical compound, a non-resinous ester of Diels-Alderadduct of anthracene and itaconic acid and an aliphatic monohydricalcohol containing more than one carbon atom.

13. As a new chemical compound, a non-resinous ester of Diels-Alderadduct of anthracene and an ethylenically unsaturated carboxylic acidand a saturated, primary, monohydric aliphatic alcohol containing morethan one carbon atom.

14. As a new chemical compound, a non-resinous diester of Diels-Alderadduct of anthracene and maleic acid and a saturated, primary, aliphaticmonohydric alcohol containing more than one carbon atom.

15. As a new chemical compound, a non-resinous diester of Diels-Alderadduct of anthracene and fumaric acid and a primary, saturated,aliphatic monohydric alcohol containing more than one carbon atom.

LYLE M. GEIGER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,262,002 Hopfl. Nov. 11, 19412,311,261 Stafl Feb. 16, 1943 OTHER REFERENCES Diels et al., Annalen derChem., vol. 486 (1931), pages 191-202.

Ardashev et al., Chem. Absta, vol. 34 (1940), page 5205.

1. AS A NEW CHEMICAL COMPOUND, A NON-RESINOUS ESTER HAVING THE FORMULA